How To Speed Controlable Fans Work ?

[qwijibow 0]

Hey guys.Without a case fan, my cpu tempreture trips over the 50 degree Centrigrade mark, and the cpu fan starts to accelerate. also, the motherboard tempreture starts to rise, along with the air inside the case, which means the graphics card cooler is less effective, as is the ram heat sinks, and the chipset heat sink.WITH a case fan, nomatter how much work i put the cpu under, the motherboard, and case air tempeture star the same, the cpu doesnt drip the 50 degree C mark, and the cpu fan stays idle.GREAT ! but the case fans are just too noisy.so here is my great idea....my it87 fan controller will run the fans between 3000 and 6000 rpm. (yes, even 3000 is too noisy)so what if i could run 2 case fans at 1500 rpm. this should be more quiet.BASICALLY.... i want to build a small device that will run from a 4pin powersupply socket (like thwhat the hard disks use) to power 2 case fans, and controll the speed, at much greater ranges that that of the it87.Each speed controlable fan has 3 wires.2 are the power supply, so the 3rd must be the speed controllable part.what kind of signal do i need to send down the 3rd wire to set the speed of the fan ???maybe a square wave form at 1500 divided by 60 Hertz ???if so, what kind of square wave form ?? + to 0, - to zero, or + to - ???what kind of amplitude in volts should the wave be ???or does the system work completely different to how i have assumed ???does anyone know ?

[jipman 0]

I think it's best not to fiddle with those things if you're not someone with good knowledge about electrics.

Anyway, if you want to reduce noice, it's best that you buy better fans, maybe zalman or arctic ones. Because they standard run at lower rpm's and are built for silence they won't produce so much noise.

If you want to control your fans, you can also use program speedfan to change the rpm's, maybe that it will allow you to set the rpm to a lower setting.

http://www.almico.com/speedfan.php

[qwijibow 0]

PWM is disabled on my motherboard, because the bios doesnt follow normal pwm standards.(some fans are at max speed when you send the it87chip a PWM 0, and some bios's actually worjk the opposite way round. rather than risk a cpu fan stopping after modpriobing it87, pwm is just dissabled in the kernel.I found out how i works, its very simple.The fans just spin as fast as they can with the given voltage, the 3rd wire (white) gives one pulse every 1/4 Pi radians. so RPM = white wire pulse * 60 / ( seconds * 8)the fan speed controller just tweks the voltage across the fan untill it gets a pre-defined fan speed for whatever tempreture the therminsors read.The take a maximum of 12 volts. i have wired them up in parrallel across the GND and +5Volt poles of the PSU (the red wire) (GND is any black wire)then i soldered the 2 white wire's together, and connected them to the correct pin of the motherboard System-Fan sockket, and changed the divider to 16 (because it will be getting double the pulses per second)because somtimes both fans mal pulse at the same time, the fan speed sensor isnt as accurate anymore, but its close enough.i replaced one 3000RPM fan with 2 underVolted 1000RPM fans.My Computer is as cold as ever, and much much more quiet.(untill someon donates me a water-cooling unit and / or a lifetime supply of dr-ice)I dont overclock, but its still nice to see my cpu shivering

[jaycee8980 0]

Ok this worked fine for me. Download the free software SPEEDFAN.it will monitor your comp temo and you can control the speends fo both of your Fans.also Motherboard Monitor is a great utility for monitering the inside temps of your HDD, your motherboard and your cpu.

[malish 0]

If you have decent knowledge in physics, the best way to improve your fan speed will be to increase voltage on the motor. You have to make sure the cooler is from a decent brand (thermaltake), because it cheap coolers have limited potential in overclocking.